PowerSteering Woes

If the fluid is full of bubbles,it sounds like there is air in the system, and it just needs to be bled. The pumps often make noises when there is air in the system. That new box was probably shipped to you dry, and needs to be bled. I do this by getting the front wheels in the air, and with the engine idling, turn the steering wheel from full left to full right, and back, multiple times, hesitating on the stops, but not staying there. I start with a low fluid level, cuz it is gonna get hot and foamy, and needs some room to burst the bubbles, and expand into. When that happens I shut 'er down and go do something else for an hour. Then return,put some fluid in, and repeat.
When the pump stops screeching and the fluid level stops dropping, then it's time for a roadtest. Good luck.